Below is a table showing the 216 web safe colors. The really safe colors are underlined:

Web-Safe Colors

*000*

300

600

900

C00

*F00*

*003*

303

603

903

C03

*F03*

006

306

606

906

C06

F06

009

309

609

909

C09

F09

00C

30C

60C

90C

C0C

F0C

*00F*

30F

60F

90F

C0F

*F0F*

030

330

630

930

C30

F30

033

333

633

933

C33

F33

036

336

636

936

C36

F36

039

339

639

939

C39

F39

03C

33C

63C

93C

C3C

F3C

03F

33F

63F

93F

C3F

F3F

060

360

660

960

C60

F60

063

363

663

963

C63

F63

066

366

666

966

C66

F66

069

369

669

969

C69

F69

06C

36C

66C

96C

C6C

F6C

06F

36F

66F

96F

C6F

F6F

090

390

690

990

C90

F90

093

393

693

993

C93

F93

096

396

696

996

C96

F96

099

399

699

999

C99

F99

09C

39C

69C

99C

C9C

F9C

09F

39F

69F

99F

C9F

F9F

0C0

3C0

6C0

9C0

CC0

FC0

0C3

3C3

6C3

9C3

CC3

FC3

0C6

3C6

6C6

9C6

CC6

FC6

0C9

3C9

6C9

9C9

CC9

FC9

0CC

3CC

6CC

9CC

CCC

FCC

0CF

3CF

6CF

9CF

CCF

FCF

*0F0*

3F0

*6F0*

9F0

CF0

*FF0*

0F3

*3F3*

*6F3*

9F3

CF3

*FF3*

*0F6*

*3F6*

6F6

9F6

*CF6*

*FF6*

0F9

3F9

6F9

9F9

CF9

FF9

*0FC*

*3FC*

6FC

9FC

CFC

FFC

*0FF*

*3FF*

*6FF*

9FF

CFF

*FFF*

Web safe colors used to be really important when 8-bit was the standard color setting for most users. However, now with most people using at least 24-bit, moving to 36-bit, they are less important, with more people using hex or decimal colors.